Cellular radio networks are constantly evolving. The third generation partnership project (3GPP) is an organization setting standards for mobile communication. The standards are structured as releases. New functionality is entered into the standard as new releases are launched.
In 3GPP Release 7 and 8, a number of enhancements have been made to improve the performance of the so called CELL_FACH state which is a Radio Resource Control (RRC) State for Random access and short transmissions. The enhancements can be listed as:                Rel-7: High Speed—Downlink Shared Channel (HS-DSCH) reception in CELL_FACH state        Rel-8: Enhanced Uplink in CELL_FACH state        Rel-8: Enhanced User Equipment (UE) Discontinuous Reception (DRX)        
The first two enhancements listed above, allow HS-DSCH and Enhanced Dedicated Channel (E-DCH) to be used as the downlink and uplink transport channels, replacing Forward Access Channel (FACH) and Random Access Channel (RACH), respectively. These new transport channels provide much higher bandwidth for UEs in CELL_FACH state.
However, UE supporting these functionalities must use the new transport channels when available. There is no option to fall back to RACH and/or FACH even when, e.g., there is a congestion in those channels. Both the UE and the network must keep on trying until the transmission is successful.
Enhanced UE DRX was introduced to reduce battery consumption. Prior to Rel-8, a UE in the CELL_FACH state is required to monitor Downlink (DL) transmissions continuously. With Enhanced UE DRX, a UE can go into a Discontinuous Reception (DRX) mode after a specified period of uplink and/or downlink inactivity. When operating in this mode, a UE only needs to monitor DL activities for a short duration once every DRX cycle. For the rest of the time, it can turn off its receiver, reducing significantly the amount of power used.
Downlink transmissions must observe the UE's DRX pattern when such a mode is activated. Data can only be sent during the short intervals when the UE is listening to the network. An option for the UE to leave the DRX mode after receiving downlink data is also provided. A prerequisite for Enhanced UE DRX is the use of the HS-DSCH as the downlink transport channel. On the UL, however, either RACH or E-DCH may be used.
The 3GPP TSG RAN meeting #54 has agreed in the Work Item “Further Enhancements to CELL_FACH” to introduce among others the following:                A second, much longer, DRX cycle.        The possibility for RRC signaling to fallback to RACH when a request for access on an E-DCH is denied.        
The behavior of a UE operating in DRX mode in CELL_FACH differs depending on whether E-DCH or RACH is configured as the uplink transport channel. When E-DCH is configured, after an uplink transmission, a UE must leave the DRX mode i.e. start to continuously monitor/listen to the High Speed Shared Control CHannel (HS-SCCH) for downlink transmissions for as long as the inactivity timer has not expired. Subsequently the UE may access the HS-DSCH.
However, when RACH is configured as the uplink transport channel, the current 3GPP specifications do not allow the UE to leave the DRX mode. Instead, after an uplink transmission, the UE would turn off the receiver immediately according to the DRX pattern. Transmission of responses on the downlink must wait for occasions when the UE is listening for/monitoring downlink transmissions. If the uplink message is for signaling purpose, e.g., for setting up or the control of time-critical applications, this waiting can introduces large and unnecessary delay.
With the introduction of a much longer DRX cycle (on the order of second.) in Rel-11, the problem becomes much more severe.
With the introduction of Fallback to RACH in Rel-11, the problem spreads even to the case where E-DCH is configured as the uplink transport channel.
There is a constant demand for improving existing systems and to provide more efficient communications in a cellular radio system. Hence, there is a need for methods and apparatuses enabling improved communications in a cellular radio system.